Call of Duty: World at War is a 2008 first-person shooter video game developed by Treyarch and published by Activision. It was released for Microsoft Windows, the PlayStation 3, Wii and Xbox 360, in November 2008. It is the fifth main installment of the Call of Duty series and returns the setting to World War II. The game is also the first title in the Black Ops story line. World at War received ports featuring different storyline versions, while remaining in the World War II setting, for the Nintendo DS and PlayStation 2. It was the first game in the series to feature the zombies mode featured in later sequels. A Windows Mobile version was also made available by Glu Mobile. The narrative for the campaign mode focuses on the Pacific and Eastern Front theaters of World War II, involving the United States, Empire of Japan, Soviet Union, and Nazi Germany. It is told from the perspectives of Marine Raider Private C. Miller, US Navy Petty Officer Locke and Red Army soldier Private Dimitri Petrenko, and is based on several historical battles. The multiplayer component of the game contains various game modes and a leveling system that allows the player to unlock additional weapons and rewards as they progress, similar to Call of Duty 4 and repeated in many following Call of Duty entries. Vehicles, in the form of tanks, that players can control appear on certain multiplayer maps. The game also contains downloadable content called "map packs", which can be purchased online. A new feature to the series was the addition of a cooperative mode, which supports up to two players locally and four players online. Development for World at War took two years and began after the release of Treyarch's previous title, Call of Duty 3, which was also set in World War II and was their first title they developed for the series. The game is based on an enhanced version of the IW engine game engine developed by Infinity Ward with increased development on audio and visual effects. Treyarch utilized the engine to make more parts of certain environments destructible and introduce limb dismemberment and realistic burns to character models. The game was announced by Activision on June 23, 2008. World at War received positive reviews from critics, with praise directed at its intensity and violent nature, though it received criticism for its lack of innovation. It was also a commercial success, selling 3 million copies in the United States within the first two months of its release, becoming one of the best-selling titles of 2008. It also marked the beginning of the Black Ops subseries, as characters from the game were carried over into its sequel, Call of Duty: Black Ops (2010). The Xbox 360 version of World at War became backwards compatible on the Xbox One in September 2016.The story begins on Makin Island on August 17, 1942. U.S. Marine Private C. Miller watches the torture and execution of his team and is about to be executed himself before being rescued by another squad of Marines, led by Corporal Roebuck and Sergeant Tom Sullivan. They then initiate the Makin Island raid, assaulting the Japanese positions on the island. Two years later, Miller's unit then participates in the Battle of Peleliu. After breaking through the Japanese lines on the Peleliu beach, Miller destroys two Type 97 Chi-Ha tanks with rocket strikes, allowing the American tanks to advance. At the end of the mission, Sullivan is fatally stabbed by a Japanese officer with a gunto. Roebuck is promoted to Sergeant and he and his squad make their way through the Peleliu swamps to launch an assault on a Japanese-held airfield to disable anti-aircraft guns. During the assault, Miller acquires a flamethrower to destroy a bunker and a bazooka to blow up the Chi-Has positioned at the airfield.[15] After pushing further inland on Peleliu, Miller and his unit take out enemy mortar crews so their tanks can proceed inland. They then proceed through the Japanese tunnels to attack the artillery-filled Point, one of the major Japanese strongholds that had destroyed many landing boats when they first landed. This allows American ships to advance, and Peleliu finally falls into American hands.[15] After American forces conquer Peleliu, the preparatory action for the Battle of Okinawa occurs, during which Petty Officer Locke, in a PBY Catalina flying boat, takes part in a raid on three merchant ships. On their way back to base, another Catalina, codenamed Hammerhead, is destroyed by Japanese Zeroes, leaving Locke and his crew alone. Meanwhile, Task Force 58 of the US 5th Fleet is attacked as part of Operation Ten-Go. Locke's PBY crew, the only one near enough to come to immediate aid, works to rescue as many American sailors as possible by fighting off Japanese PT boats and kamikaze planes. With the PBY almost completely destroyed and ammunition on Locke's .50 cal running out, all hope seems lost.